另外唔識做個時可以自救,又見到幅圖四四方方
introduce coordinate to the geom,
let B be (0,0)
A(0,6) ,C(6.0) ,F(0,2)
計到AE slope =-6/3=-2 =>FG slope =1/2
寫到equation of AE 同equation of FG
計機solve 相交點H coord.
再put x=6 落equation of FG 可以計到y- coordinate of G ,(即係CG)
有齊H ,G,C,E 四點coordinate ,就計到required area
(理論上已經有齊哂題目中所有點嘅coordinate, 乜area 都計到)